CN105840335B - Two stroke engine cylinder body enclosed scavenging path - Google Patents

Abstract

The invention relates to the technical field of general small-sized two-stroke engines, in particular to a closed-type scavenging passage for a cylinder block of a layered scavenging two-stroke engine. The closed scavenging passage includes a closed scavenging channel of the cylinder body, a groove channel on the flange surface of the cylinder body and a thin plate that cooperates with the groove channel to form an intake channel. The channel, the closed scavenging channel, the groove channel and the expansion channel are connected. The cooperation between the flange surface of the cylinder body and the different through holes on the thin plate forms closed scavenging passages of different lengths in the cylinder body. The increase in the length of the closed scavenging passage is conducive to the stratification of pure air and mixed gas, and improves the pilot sweeping of pure air. Exhaust gas stability, reducing the loss of mixed gas, improving the stability of mixed gas scavenging, increasing the scavenging speed, and stabilizing the scavenging direction can effectively improve engine power, high and low speed stability, and reduce exhaust emissions.

Description

Two-stroke engine cylinder closed scavenging passage

technical field

The invention relates to the technical field of general small-sized two-stroke engines, in particular to a closed-type scavenging passage for a cylinder block of a layered scavenging two-stroke engine.

Background technique

China, the European Union, the United States and other countries and regions have set lower exhaust emission limits for small general-purpose two-stroke engines, especially for hand-held tools such as brush cutters, chain saws, and blowers. The current hand-held tools mainly adopt two methods of exhaust gas after-treatment technology and pilot pure air stratified scavenging technology to reduce exhaust emissions.

At present, in stratified scavenging two-stroke engines, a part of the air is pre-stored in the scavenging channel to scavenge first, so as to reduce the phenomenon that the mixed gas is directly discharged with the exhaust gas without burning, thereby effectively reducing harmful components in the exhaust gas such as HC and CO. compounds, protecting the environment. For example, ZL201520130727.1 is a layered scavenging two-stroke gasoline engine cylinder, which has a large scavenging channel and a small scavenging channel with different cross-sectional areas. A throttle plate is arranged in the small scavenging channel, and the air is stored in the scavenging channel through the piston. During scavenging, the air enters the combustion chamber of the cylinder block to remove the exhaust gas, which can reduce the phenomenon of part of the unburned mixture existing in ordinary two-stroke gasoline engines escaping with the exhaust gas, and effectively reduce the emission of compounds such as HC and CO in the exhaust gas. However, a large number of tests have shown that when the engine is running at high speed, the amount of air stored in the scavenging passage is relatively small. When scavenging, there is not only air, but also part of the unburned mixture involved in the removal of exhaust gas. Therefore, the exhaust gas cannot be completely exhausted. Eliminating the emission of compounds such as HC and CO is not conducive to environmental protection. Therefore, there is an urgent need for a closed scavenging path that stores a lot of gas, is conducive to the stratification of air and mixed gas, and has a long path.

Contents of the invention

The object of the present invention is to provide a closed type scavenging passage of a two-stroke engine cylinder which can increase the length of the closed type scavenging passage, has a simple structure, can realize molds, is low in cost and is easy to process.

The technical solution of the present invention: a closed type scavenging channel of a two-stroke engine cylinder, which is characterized in that it includes a closed type scavenging channel of the cylinder, a groove channel provided on the flange surface of the cylinder and a channel covering the cylinder The flange surface cooperates with the groove channel to form a thin plate of the air intake channel; the groove channel is a variable cross-section structure with at least one expansion channel, and the closed scavenging channel, the groove channel and the expansion channel are connected.

Preferably, the closed scavenging passages are respectively provided on both sides of the cylinder body, and at least one is provided on each side.

Further, at least one through hole is provided on the thin plate.

Further, the through hole matches the shape of the closed scavenging port.

Further, the through hole matches the shape of the opening of the expansion channel.

The beneficial effect is: the scavenging passage can realize that the mixed gas of the crankcase enters the scavenging passage passage from different positions, enters the closed scavenging passage, and finally enters the combustion chamber of the cylinder block by using thin plate-shaped parts with different opening positions. , in order to increase the length of the closed scavenging channel. Experiments have proved that the increase in the length of the closed scavenging channel is beneficial to the stratification of pure air and mixed gas, improving the stability of pure air pilot scavenging exhaust gas, reducing the loss of mixed gas, and improving the mixing efficiency. The stability of air scavenging, increasing the scavenging speed, and stabilizing the scavenging direction can effectively improve the power of the engine, the stability of high and low speeds, and reduce exhaust emissions.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the present invention. The exemplary embodiment and its description are used to explain the present invention, and do not constitute an improper limitation of the present invention.

Figure 1 is a schematic diagram of the scavenging passage on the flange surface of the cylinder block;

Fig. 2 is a schematic diagram of a thin plate at an opening position;

Fig. 3 is a schematic view of the closed scavenging passage formed by the cooperation of the thin plate shown in Fig. 2 and the scavenging passage of the cylinder body in Fig. 1 and the flow direction of the mixed gas in the passage;

Fig. 4 is a thin plate schematic diagram of an opening position;

Fig. 5 is a schematic diagram of a closed scavenging passage formed by the cooperation of the thin plate shown in Fig. 4 and the scavenging passage of the cylinder block in Fig. 1, and a schematic diagram of the flow direction of the mixed gas in the passage;

Fig. 6 is a schematic diagram of a thin plate at an opening position;

Fig. 7 is a schematic view of the closed scavenging passage formed by the cooperation of the thin plate shown in Fig. 6 and the scavenging passage of the cylinder block in Fig. 1 and the flow direction of the mixed gas in the passage;

Figure 8 is a schematic diagram of the flow direction of the mixed gas entering the cylinder through the closed scavenging passage on the cylinder;

Description of serial numbers in the accompanying drawings: 1, cylinder body; 2a, 2b, closed scavenging passage; 3a, 3b, groove channel; 4a, 4b, expansion channel; 5, cylinder body flange surface; 6, 7, 8, Sheets; 6a, 7b, 8a, 8b, sheet openings.

detailed description

As shown in Figures 1 to 8, the closed scavenging passage of the two-stroke engine cylinder includes the closed scavenging channels 2a, 2b of the cylinder 1, and the groove channels 3a, 3b on the flange surface 5 of the cylinder. (including expansion channels 4a, 4b), thin plates 6, 7, 8 (including thin plate openings 6a, 7b, 8a, 8b).

The closed scavenging channels 2a, 2b are located on both sides of the cylinder body 1, the groove channels 3a, 3b are located on the flange surface of the cylinder body, and the expansion channels 4a, 4b are the variable cross-section structures of the groove channels 3a, 3b. The air passages 2a, 2b, the groove passages 3a, 3b, and the expansion passages 4a, 4b are connected.

The thin plates 6, 7, 8 are provided with at least one thin plate opening 6a, 7b, 8a, 8b, and the thin plates 6, 7, 8 cover the flange surface 5 of the cylinder body, and are respectively connected with the groove channels 3a, 3b, the expansion channels 4a, 4b, the closed scavenging passages 2a and 2b form cylinder closed scavenging passages of different lengths.

Specific working process: first embodiment: when the thin plate 6 is covered on the flange surface 5 of the cylinder body, and the thin plate opening 6a is matched with the closed scavenging air passage 2a, the mixed gas in the crankcase enters the closed type through the thin plate opening 6a. The scavenging channel 2a, the other part is respectively along the groove channel 3b→expanding channel 4b→groove channel 3b→entering the closed scavenging channel 2b, and along the groove channel 3a→expanding channel 4a→groove channel 3a→entering the closed The scavenging passage 2b finally enters the cylinder body to increase the length of the closed scavenging passage.

Second embodiment: when the thin plate 7 covers the flange surface 5 of the cylinder body and the thin plate opening 7b is matched with the closed scavenging passage 2b, the mixed gas in the crankcase enters the closed scavenging passage 2b through the thin plate opening 7b , the other part respectively along the groove channel 3b→expansion channel 4b→groove channel 3b→entering the closed scavenging channel 2a, and along the groove channel 3a→expansion channel 4a→groove channel 3a→entering the closed scavenging channel 2a , and finally enter the cylinder to increase the length of the closed scavenging passage.

Third embodiment: when the thin plate 8 covers the flange surface 5 of the cylinder body, and the thin plate openings 8a, 8b are matched with the expansion channels 4a, 4b respectively, a part of the mixed gas in the crankcase enters the thin plate opening 8a and passes through the thin plate opening 8a → Expansion channel 4a → Groove channel 3a → Closed scavenging channel 2a; and through sheet opening 8a → Expansion channel 4a → Groove channel 3a → Closed scavenging channel 2b; another part of the mixture in the crankcase enters the sheet opening 8b, through thin plate opening 8b→expansion channel 4b→groove channel 3b→closed scavenging channel 2a; and through thin plate opening 8b→expanded channel 4b→groove channel 3b→closed scavenging channel 2b. The final mixture enters the cylinder block to increase the length of the closed scavenging path.

Finally, the mixed gas respectively passes through the closed scavenging passage 2a and the closed scavenging passage 2b into the cylinder body 1 to complete the scavenging work.

The beneficial effect is: the scavenging passage can realize that the mixed gas of the crankcase enters the scavenging passage passage from different positions, enters the closed scavenging passage, and finally enters the combustion chamber of the cylinder block by using thin plate-shaped parts with different opening positions. , in order to increase the length of the closed scavenging passage. Experiments have proved that the increase in the length of the closed scavenging passage is beneficial to the stratification of pure air and mixed gas, improving the stability of pure air pilot sweeping exhaust gas, reducing the loss of mixed gas, and reducing exhaust gas. emission and protect the environment.

Although the structure and method for implementing the present invention have been described in detail above, the present invention is not limited thereto. Those skilled in the art can adjust the shape, size, In terms of other detailed structures, modifications are made to the embodiments, and the modifications are still included in the present invention.

Claims (2)

1. A kind of 1. two stroke engine cylinder body enclosed scavenging path, it is characterised in that：Enclosed scavenging air belt, cylinder body method including cylinder body The recess channels and overlay on cylinder body flange face the thin plate that inlet channel is cooperatively formed with recess channels that blue face is provided with；It is described recessed Groove passage is the variable section structure at least provided with an expanding channel, and the enclosed scavenging air belt, recess channels, expanding channel are connected It is logical；Match on the thin plate at least provided with a through hole, the through hole and the shape at enclosed scavenging road junction, or the through hole with The shape of expanding channel mouth matches.
2. 2. two stroke engine cylinder body enclosed scavenging path according to claim 1, it is characterised in that：The enclosed scavenging Road is separately positioned on the both sides of cylinder body, and per side at least provided with one.